JP2872799B2 - Semiconductor sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a semiconductor sealing method used for sealing a semiconductor element to be mounted on a circuit board on the circuit board.

[Prior art]

In a hybrid integrated circuit, after a conductor pattern is formed on a circuit board, a bare chip is mounted as a semiconductor device together with passive elements such as resistors. A conductor pattern to be connected to a terminal of the bare chip is formed on a peripheral portion of the bare chip on the circuit board, and each terminal of the bare chip and the conductor pattern are electrically connected by conductor wires by wire bonding. After such an electrical connection is made, a guard ring as a damping frame for damping the sealing resin is formed of the sealing resin in a range surrounding the conductor wire and the bare chip, and the guard ring is solidified. Then, the inside is filled with a sealing resin, and the bare chip, the conductor wire and the conductor pattern of the peripheral portion are sealed with the sealing resin.

[Problems to be solved by the invention]

Incidentally, the guard ring used for resin sealing of such a semiconductor element is for damping the sealing resin, and ideally, a resin having lower fluidity than the sealing resin is used. From the viewpoint of workability, it is desirable that the guard ring be cured immediately, and a resin capable of setting a sufficient height in a narrow range is desired. Conventionally, a thixotropic resin different from the sealing resin is used for the guard ring, and its adjustment is very troublesome. Even if the resin for guard ring is used, the fluidity is slightly different, and there is no optimal resin for guard ring,
In order to obtain a sufficient height, the amount of dripping per unit area increases, and the solidification spreads due to its fluidity during solidification, which causes a reduction in mounting efficiency of components on a circuit board. Therefore, the present invention is to heat the sealing resin forming the guard ring to accelerate the curing, to form an optimal guard ring to realize efficient resin sealing, and to perform a heat treatment for forming the guard ring. It is an object of the present invention to provide a semiconductor encapsulation method in which the adverse effects of the above are avoided by airflow.

[Means for Solving the Problems]

That is, according to the semiconductor sealing method of the present invention, a guard ring (18) is formed around the semiconductor on a circuit board (2) on which a semiconductor element (bare chip 4) is installed, and a sealing resin (16) is formed inside the guard ring (18). ) To seal the semiconductor element on the circuit board in a semiconductor sealing method, wherein a sealing resin supply means (syringe 20 and needle 22) is provided on a portion of the circuit board where the guard ring is to be formed. While supplying the sealing resin, the sealing resin supplied to the circuit board is blown with hot air (28) from hot air supply means (a hot air generating source 24 and a hot air supply pipe 26) to be thermally cured, and The movement of the hot air to the resin stop means
It is characterized by being blocked by 4).

[Action]

Since the sealing resin forming the guard ring can be rapidly cured by heating on the circuit board, the curing allows the guard ring having a sufficient height to be formed with a small amount of resin. Since the hardening of the guard ring is accelerated and sufficient strength can be obtained in a short time, the sealing resin can be filled immediately after the formation of the guard ring. Then, the hot air blown to the sealing resin for forming the guard ring is blown off by an air current to prevent heating of the sealing resin on the side of the sealing resin supply means, and the sealing resin before being supplied to the circuit board. Degradation can be prevented.

【Example】

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. 1 and 2 show an embodiment of the semiconductor sealing method of the present invention. As shown in FIGS. 1 and 2A, a circuit board 2 is formed of an insulating material such as alumina or ceramic, and a bare chip 4 as a semiconductor element is formed on the surface of the circuit board 2. (B) The conductor 6 is formed by printing on the portion where the {circle around (1)} is to be mounted, and the conductor pattern 8 is formed at regular intervals on the conductor 6. The conductor pattern 8 forms a circuit pattern with circuit components (not shown) and other functional circuits. As shown in FIG. 2B, the bare chip 4 is fixed to the upper surface of the conductor 6 with a conductive adhesive 10 and the semiconductor substrate of the bare chip 4 is electrically connected to the conductor 6. Electrodes formed on the edge of bare chip 4
A conductor wire 14 is connected between the conductor pattern 12 and the corresponding conductor pattern 8 by wire bonding, and is electrically connected. Then, a guard ring 18 is formed with a sealing resin 16 in an area surrounding the bare chip 4 and the conductor pattern 8 to which the conductor wires 14 are connected. That is, as shown in FIG. 1, a syringe 20 is provided as a sealing resin supply means, and the sealing resin 16 is continuously sealed at a tip end thereof by a predetermined amount by pressing the syringe 20 side. A needle 22 for dropping the resin 16 is attached. Therefore, the sealing resin 16 is continuously supplied from the needles 22 to the upper surface of the circuit board 2 in a one-stroke form. It is formed by the stopper resin 16. In the vicinity of the syringe 20, a hot air supply pipe 26 connected to a hot air generation source 24 installed as a hot air supply means is exposed, and its tip is in the vicinity of the needle 22, that is, the needle.
It is directed from 22 onto the sealing resin 16 immediately after dropping. Therefore, the sealing resin 16 dropped on the circuit board 2 is heated by the hot air 28 injected from the hot air supply pipe 26 and is thermally cured. In addition, near the syringe 20, hot air 28
And airflow as a blocking means for blocking the needle 22,
That is, an air supply pipe 32 connected to the air source 30 is provided as air curtain forming means for forming an air curtain. The air supply pipe 32 is installed to face the hot air supply pipe 26 with the syringe 20 and the needle 22 interposed therebetween.
The tip of the air injection nozzle is bent into an L-shape toward the needle 22, and the injection air 34 is
It is arranged to form an air curtain that protects 22. In other words, the hot air 28 is pushed in the direction of the jet air 34 by the air curtain formed by the jet air 34, and the sealing resin 16 in the syringe 20 and the needle 22 is protected, thereby preventing thermal deterioration due to the hot air 28. You. Therefore,
The supply of the sealing resin 16 from the needle 22 is dropped onto the circuit board 2 with necessary fluidity without being obstructed. Then, the sealing resin 16 that has received the hot air 28 is heated by the heat energy from the hot air 28 and is thermally cured by the heating, so that the flow of the sealing resin 16 is prevented, and the sealing resin 16 is shown in FIG. 2C. Thus, the guard ring 18 has a sufficient height and strength in a narrow range. Next, the inside of the guard ring 18 is filled with the sealing resin 16 from the needle 22 using the syringe 20 as shown in FIG. 2D, and as shown in FIG.
A resin film having a sufficient thickness is formed on the bare chip 4 to complete the resin sealing. In such resin sealing, a guard ring 18 having sufficient strength and height is formed with a small amount of the sealing resin 16 by utilizing the thermosetting of the sealing resin 16, and a sealing ring similar to the guard ring 18 is formed therein. Sealing is performed with the sealing resin 16. In particular, since the sealing resin 16 on which the guard ring 18 is to be formed can be prevented from flowing out by thermosetting, the operation of the syringe 20 is easy and the guard ring 18 with high accuracy is formed. Since the hot air 28 used for this thermosetting is blocked by the air curtain of the blast air 34, the hot air 28 does not hit the sealing resin 16 before the supply of the syringe 20 or the needle 22 on the sealing resin supply means side. The deterioration of the sealing resin 16 is prevented. Therefore, the reliability of the guard ring 18 is improved. According to experiments, when epoxy resin is used as the sealing resin 16, the surface temperature of the sealing resin 16 can be raised to 150 ° C. to 200 ° C. by the hot air 28 from the hot air generating source 24, thereby The resin 16 was thermally cured, and the strength and height sufficient to fill the sealing resin 16 covering the bare chip 4 could be set.

【The invention's effect】

As described above, according to the present invention, the following effects can be obtained. (A) Hot air is blown onto the sealing resin, and the sealing resin is thermally cured by the hot air to form the guard ring. Therefore, the time for forming the guard ring is short, and the guard ring can be filled with the sealing resin immediately. The hardening can be performed to a sufficient degree, the formation of the guard ring and the filling of the inside thereof with the sealing resin can be performed in the same step, so that the manufacturing time can be reduced and the manufacturing cost can be reduced. (B) The curing speed of the sealing resin for forming the guard ring can be increased by thermosetting, so that an ideal guard ring can be formed, and the sealing resin forming the guard ring and the inside of the guard ring are filled. The same sealing resin to be used can be used, and it is not necessary to use a special sealing resin. Therefore, the manufacturing cost can be reduced from the viewpoint of materials. (C) Unnecessary spreading to the circuit board surface due to the fluidity of the sealing resin for forming the guard ring can be prevented, which can contribute to high-density mounting of the circuit board. (D) It is possible to block the hot air applied to the sealing resin on which the guard ring is to be formed, thereby preventing the heating of the sealing resin on the side of the sealing resin supply means, and removing the sealing resin before being supplied to the circuit board. It can protect against thermal deterioration due to hot air, the quality of guard ring,
Reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the semiconductor sealing method of the present invention, and FIG. 2 is a sectional view showing one embodiment of the semiconductor sealing method of the present invention. 2 ... circuit board 4 ... bare chip (semiconductor element) 16 ... sealing resin 18 ... guard ring 20 ... syringe (sealing resin supply means) 22 ... needle (sealing resin supply means) 24 ... hot air Source (hot air supply means) 26 Hot air supply pipe (hot air supply means) 28 Hot air 34 Air jet (air flow)

Claims (1)

(57) [Claims] A semiconductor ring for forming a guard ring around a semiconductor on a circuit board on which a semiconductor element is installed, and filling the inside with a sealing resin to seal the semiconductor element on the circuit board. In the stopping method, while supplying the sealing resin from a sealing resin supply unit to a portion of the circuit board where the guard ring is to be formed, the sealing resin supplied to the circuit board is supplied with hot air from a hot air supply unit. A semiconductor encapsulation method, wherein the semiconductor device is blown and thermally cured, and the movement of the hot air toward the encapsulation resin supply unit is blocked by an air current.